1. Field of the Invention
The present invention relates to a noise suppressing connector which adopt a noise filtering structure formed on a metal casing.
2. Description of the Prior Art
Conventionally, various noise suppressing connectors adopting a noise filtering structure have been invented by now, a case in point being the one disclosed in Japanese Patent application laid-open No. 59-184478 as shown in FIGS. 6 and 7, which respectively represent a longitudinal sectional view showing a noise preventing connector and a magnified sectional view thereof.
In FIG. 6, reference numeral 16 denotes a noise suppressing connector comprising an insulating housing 17, a metal casing 19 having a ground contact 18 and disposed at the end portion of the insulating housing 17, an alumina plate 20 having a capacitor C' and disposed in the middle portion of the metal casing 19, and a pin terminal 22 firmly inserted through a terminal insertion hole 21 formed in the alumina plate 20, whereby the pin terminal 22 is electrically conducted to the metal casing 19 by way of the capacitor C' formed on the alumina plate 20.
In FIG. 7, reference numeral 23 denotes a noise filtering structure in the above noise suppressing connector 16, wherein the noise filtering structure 23 comprises the above described capacitor C'. The capacitor C' itself comprises a ground leading layer 24 formed on the alumina plate 20, a plurality of dielectric layers 25 formed on the ground leading layer 24, a terminal electrode layer 26 formed on one of the plurality of dielectric layers 25 with one end portion thereof 26a extended up to the inner side of the above described terminal insertion hole 21, a plurality of insulating layers 27 formed on the terminal electrode layer 26, wherein the terminal electrode layer 26 is connected to the pin terminal 22 by means of a soldering 28, and the ground leading layer 24 is connected to the metal casing 19 also by means of a soldering 29. FIG. 8 is an illustration showing a block diagram of a circuit wherein the pin terminal 22 is grounded by way of the thus constructed capacitor C' formed on the alumina plate 22.
However, in a conventional structure constructed as above, since the alumina plate 20 has to be connected to the metal casing 19 by a soldering 29, many manufacturing processes are required, and incomplete connection therebetween is frequently observed due to a badly performed soldering or the like. Further, since the alumina plate 20 itself is not strong enough, it is likely to be broken when some impact is applied thereto.